Methods for improving adhesion on dielectric substrates

ABSTRACT

Various embodiments described herein provide for substrate structures including uniform plating seed layers, and that provide favorable adhesion on dielectric substrate layers. According to some embodiments, a methods for forming a magnetic recording pole is provided comprising: forming an insulator layer; forming a trench in the insulator layer; forming an amorphous seed layer over the insulator layer; forming an adhesion layer over the amorphous seed layer, the adhesion layer comprising a physical vapor deposited (PVD) noble metal; forming a plating seed layer over the adhesion layer, the plating seed layer comprising chemical vapor deposited (CVD) Ru; and forming a magnetic material layer over the plating seed layer.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 13/480,278 filed on May 24, 2012, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This invention relates to dielectric substrates and, more particularly, improving adhesion on dielectric substrates, such as those used in magnetic recording poles for storage devices.

BACKGROUND

When fabricating Perpendicular Magnetic Recording (PMR) writer main poles (hereafter referred to simple as “PMR poles”), generally a trapezoidal shaped trench is etched into a thick substrate layer (e.g., alumina) and the trench is then filled with a magnetic material by way of a plating process. It has been shown that during fabrication, lining the inside of the trench and cover the top surface of the thick substrate layer with a plating seed layer can achieve a substantially void-free fill of the trench (with the magnetic material) while retaining desirable properties (e.g., as high saturation magnetization, low easy/hard axis coercivity, low anisotropy, high frequency response, and low remnant magnetization).

Using ruthenium (Ru) when plating high moment magnetic materials, such as those used in PMR poles, is known to provide the high moment magnetic materials with desirable properties for effective functioning of the magnetic head. Additionally, it can be useful and desirable to encapsulate the PMR pole with a soft magnetic shield, where the soft magnetic shield is plated over the top and sides of the PMR pole with an intervening non-magnetic spacer layer that also serves as a plating seed. Like with high momentum magnetic materials, Ru is well suited for the plating of soft high moment magnetic materials. Of known deposition techniques, Chemical Vapor Deposition (CVD) is one commercially viable method for providing conformal Ru deposition, and is often used for electroplating seed layers during PMR pole fabrication.

Unfortunately, it is a challenge to form a smooth, highly conformal layer of Ru on the inside of the trench or the exposed surfaces of the three dimensional PMR pole structure while also providing good thickness control and uniformity over the entire PMR pole structure. Additionally, employing a Chemical Vapor Deposition (CVD) Ru-based film as a Ru layer is known to cause peeling/delamination issues during plating processes or chemical mechanical polishing (CMP). This is especially true where the CVD Ru-based film is deposited from RuO₄-containing precursor and where the CVD-Ru-based film is deposited on a dielectric, such as an amorphous seed layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not limitation, in the figures of the accompanying drawings in which:

FIGS. 1A-1G are diagrams illustrating cross-sectional views of an exemplary substrate structure during a process for forming a substrate structure in accordance with some embodiments;

FIG. 2 is flowchart illustrating an exemplary method for forming substrate structures in accordance with some embodiments;

FIG. 3 is a transmission electron microscopy (TEM) image of a an exemplary substrate structure in accordance with some embodiments;

FIG. 4 is a diagram illustrating an exemplary disk drive including a read-write head formed in accordance with some embodiments.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth, such as examples of specific layer compositions and properties, to provide a thorough understanding of various embodiment of the present invention. It will be apparent however, to one skilled in the art that these specific details need not be employed to practice various embodiments of the present invention. In other instances, well known components or methods have not been described in detail to avoid unnecessarily obscuring various embodiments of the present invention.

The terms “over,” “under,” “between,” and “on” as used herein refer to a relative position of one layer with respect to other layers. As such, for example, one layer disposed over or under another layer may be directly in contact with the other layer or may have one or more intervening layers. Moreover, one layer disposed between two layers may be directly in contact with the two layers or may have one or more intervening layers. In contrast, a first layer “on” a second layer is in contact with that second layer. Additionally, the relative position of one layer with respect to other layers is provided assuming operations are performed relative to a substrate without consideration of the absolute orientation of the substrate.

Various embodiments described herein provide for substrate structures including uniform plating seed layers, and that provide favorable adhesion over dielectric substrate layers. According to some embodiments, methods for forming such substrate structures are provided, where the methods comprising: forming an amorphous seed layer; forming an adhesion layer over the amorphous seed layer, the adhesion layer comprising a physical vapor deposited (PVD) noble metal; and forming a plating seed layer over the adhesion layer, the plating seed layer comprising chemical vapor deposited (CVD) Ru. According to some embodiments, substrate structures are provided, where the products comprises: an amorphous seed layer disposed over the insulator; an adhesion layer disposed over the amorphous seed layer, the adhesion layer comprising a physical vapor deposited (PVD) noble metal; and a plating seed layer disposed over the adhesion layer, the plating seed layer comprising chemical vapor deposited (CVD) Ru.

By inserting a physical vapor deposited (PVD) Ru-film adhesion layer between a CVD Ru-layer and an amorphous seed layer, various embodiments can achieve favorable adhesion between the CVD Ru-layer and the amorphous seed layer (i.e., reduce the chances of CVD Ru delamination) and excellent film properties on amorphous the seed layers. Use of various embodiments may also result in the CVD Ru layer exhibiting a smooth surface and excellent step coverage. For some embodiments, the physical vapor deposited (PVD) Ru-film adhesion layer can improve adhesion between a CVD RU layer and a dielectric material typically used in amorphous seed layer.

Usually, when a CVD Ru-layer is deposited on substrate materials typically used in a Perpendicular Magnetic Recording (PMR) read/write head, the CVD-Ru-layer often exhibits different deposition rates, extremely rough surface, and significantly poor within wafer (wiw) uniformity, which all can have negative impact on the PMR read/write head's yield and performance. For some embodiments, such issues can be addressed by forming a thin amorphous seed layer underneath the CVD Ru-based layer to block the substrate materials' impact on the CVD Ru growth mechanism. Depending on the embodiment, the amorphous seed layer may comprise a dielectric material, such as TaO_(x), TiO_(x), AlO_(x), SiO_(x), or WO_(x). In order to promote adhesion between the CVD Ru-based layer and the dielectric material and prevent extensive delamination by the CVD Ru-based layer, an adhesion layer comprising a physical vapor deposited (PVD) noble metal may be inserted between the CVD Ru-layer and the dielectric material layer.

For some embodiments, the substrate structure may be utilized in a magnetic recording pole for a storage device, such as a Perpendicular Magnetic Recording (PMR) writer main pole. As such, some embodiments provide for a method for forming a magnetic recording pole comprising: forming an insulator layer; forming a trench in the insulator layer; forming an amorphous seed layer over the insulator layer; forming an adhesion layer over the amorphous seed layer, the adhesion layer comprising a physical vapor deposited (PVD) noble metal; forming a plating seed layer over the adhesion layer, the plating seed layer comprising chemical vapor deposited (CVD) Ru; and forming a magnetic material layer over the plating seed layer. Additionally, some embodiments provide for a magnetic recording pole in accordance with some embodiments may comprise: an insulator layer; an amorphous seed layer disposed over the insulator; an adhesion layer disposed over the amorphous seed layer, the adhesion layer comprising a physical vapor deposited (PVD) noble metal; a plating seed layer disposed over the adhesion layer, the plating seed layer comprising chemical vapor deposited (CVD) Ru; and a magnetic material layer disposed over the plating seed layer.

FIGS. 1A-1G are diagrams illustrating cross-sectional views of an exemplary substrate structure 100 during a process for forming a substrate structure in accordance with some embodiments. Depending on the embodiments, the substrate structure 100 eventually formed may be for a Perpendicular Magnetic Recording (PMR) read/write head and, more specifically, a PMR writer pole. In accordance with some embodiments, the process for forming the substrate structure 100 may include deposition of an amorphous seed layer for providing a substantially uniform and conformal Ru plating seed layer, and deposition of an adhesion layer over the amorphous seed layer to promote adhesion between the amorphous seed layer and one or more layers deposited over the adhesion layer (e.g., a plating seed layer).

FIG. 1A is a cross-sectional view of the substrate structure 100 including a mask layer 102 over an insulator substrate 104 disposed over a lower substrate or base layer 106 in accordance with some embodiments. The mask layer 102 may comprise tantalum (Ta) or another suitable material, the insulator substrate 104 may comprise alumina or another suitable material, and the lower substrate 102 may comprise chromium (Cr) or another suitable layer. In certain embodiments, the Cr-base layer is an etching stop layer for subsequent etching of the insulator substrate 104.

In FIG. 1B, the mask layer 102 may be patterned to form a patterned mask 108, having an opening 110 over a region of insulator substrate 104 where a damascene trench is intended to be formed. FIG. 1C provides a cross-sectional view of the substrate structure 100 after an etching process has removed a portion of the insulator substrate to form a trench 112 in accordance with some embodiments. For particular embodiments, the etching process is a reactive ion etching process, which can produce damascene trench.

FIG. 1D provides a cross-sectional view of the substrate structure 100 after an amorphous seed layer 114 including a metal oxide, metal nitride or metal alloy has been deposited over the substrate structure 100 in accordance with some embodiments. According to some embodiments, the amorphous seed layer 114 may include any of the valve metals, such as Al, Ti, Tu, Ta, W, Ta, Hf, Nb, Zr or Si. Additionally, for some embodiments, the amorphous seed layer 114 may comprise TaO_(x), TiO_(x), AlO_(x), SiO_(x), or WO_(x).

The amorphous seed layer 114 may be deposited using a physical vapor deposition (PVD), a chemical vapor deposition (CVD), or an atomic layer deposition (ALD) process. In various embodiments, the amorphous seed layer 114 may be deposited as a metal film and then permitted to oxidize by ambient air or by an accelerant. In some embodiments, the accelerant may be a material including RuO₄. In particular embodiments, the amorphous seed layer 114 may be deposited as a metal film and then allowed to oxidize by a combination of ambient air and RuO₄.

In certain embodiments, where the amorphous seed layer 114 includes Ta, a chemical vapor deposition (CVD) Ru plating seed layer over the amorphous seed layer 114 can provide substantially more uniform and conformal CVD Ru plating seed layer than the same CVD Ru plating layer over a Ta/Ru seed layer.

Depending on the embodiment, an additional control layer may be disposed over the substrate structure 100 prior to depositing the amorphous seed layer 114 to form a narrower trench. The control layer may be added to help control the final shape and track width of the substrate structure 100 when used in a Perpendicular Magnetic Recording (PMR) writer pole. The control layer can include one or more layers of alumina deposited via atomic layer deposition (ALD). Control layer may include layers of other suitable materials deposited by suitable deposition methods.

In accordance with some embodiments, a surface treatment material may be disposed over the substrate structure 100 prior to depositing the amorphous seed layer 114, thereby reducing delamination effects during the deposition process. According to some embodiments, the surface treatment material may be an etching material that can be deposited using deposition processes known in the art.

FIG. 1E provides a cross-sectional view of the substrate structure 100 after an adhesion layer 116 including a noble metal has been deposited over the substrate structure 100 in accordance with some embodiments. According to one embodiment, the adhesion layer 116 may include such noble metals as comprises Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au. The adhesion layer 116 may be deposited using a physical vapor deposition (PVD). By inserting a physical vapor deposited (PVD) noble metal adhesion layer, such as a PVD Ru-film adhesion layer, between a CVD Ru-layer and an amorphous seed layer, various embodiments can achieve favorable adhesion between the CVD Ru-layer and the amorphous seed layer (i.e., reduce the chances of CVD Ru delamination) and excellent film properties on amorphous the seed layers.

FIG. 1F provides a cross-sectional view of the substrate structure 100 after a plating seed layer 118 including Ru has been deposited over the adhesion layer 116 in accordance with some embodiments. In some embodiments, the plating seed layer 118 may be deposited using a chemical vapor deposition (CVD) process. In various embodiments, other suitable deposition techniques, such as atomic layer deposition (ALD), can be used to deposit the plating seed layer 118 over the adhesion layer 116.

FIG. 1G provides a cross-sectional view of the substrate structure 100 after a layer of magnetic material 120 has been plated over the plating seed layer 118 in accordance with some embodiments. For several embodiments, the magnetic material 120 may comprise a high moment magnetic material, and may include such materials as NiFe, CoNiFe, or CoFe.

In various embodiments, the process can perform the sequence of actions in a different order, can skip one or more of the actions, or can perform additional actions. Additionally, in some embodiments, one or more of the actions may be performed simultaneously.

In several embodiments, additional layers can be included and/or actions taken as part of a Perpendicular Magnetic Recording (PMR) writer pole fabrication process. For instance, a chemical mechanical planarization (CMP) stop layer may be deposited and used as a stop to planarize the surface of a magnetic pole and thereby accurately control a height of the magnetic pole for the PMR writer pole. In some embodiments, other layers and actions for the PMR writer pole fabrication process are used.

FIG. 2 is flowchart illustrating an exemplary method 200 for forming substrate structures in accordance with some embodiments. Various embodiments includes deposition of an amorphous seed layer for providing a substantially uniform and conformal Ru plating seed layer, and deposition of an adhesion layer over the amorphous seed layer to promote adhesion between the amorphous seed layer and one or more layers deposited over the adhesion layer (e.g., a plating seed layer).

At step 202, an insulator layer is formed, possibly over a lower substrate or base layer. In some embodiments, the insulator layer may be deposited over an etch stop layer, such as a chromium (Cr) stop layer. Subsequently, at step 204, a portion of the insulator layer is removed to form a trench. For certain embodiments, the insulator removal and formation of the trench may use an etching process, such as a reactive ion etching process or other suitable process.

At step 206, an amorphous seed layer is formed, possibly over the insulator layer formed at step 202, where the amorphous seed layer includes a metal oxide or a metal nitride. According to some embodiments, the amorphous seed layer 114 may include any of the valve metals, such as Al, Ti, Tu, Ta, W, Ta, Hf, Nb, Zr or Si. Additionally, for some embodiments, the amorphous seed layer 114 may comprise TaO_(x), TiO_(x), AlO_(x), SiO_(x), or WO_(x). In some embodiments, the amorphous seed layer may be deposited using a physical vapor deposition (PVD), a chemical vapor deposition (CVD), or an atomic layer deposition (ALD) process. In several embodiments, intervening sub-processes may be performed on the insulator layer prior to deposition of the amorphous seed layer as described above.

At step 208, an adhesion layer is formed, possibly over the amorphous seed layer formed at step 206. The adhesion layer may comprise a noble metal, such as Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au. The adhesion layer may be deposited using a physical vapor deposition (PVD). Inserting a physical vapor deposited (PVD) noble metal adhesion layer, such as a PVD Ru-film adhesion layer, between a CVD Ru-layer and an amorphous seed layer may achieve favorable adhesion between the CVD Ru-layer and the amorphous seed layer (i.e., reduce the chances of CVD Ru delamination) and excellent film properties on amorphous the seed layers.

At step 210, a plating seed layer is formed, possibly over the adhesion layer formed at step 208. The plating seed layer may include Ru on the amorphous seed layer, such chemical vapor deposition (CVD) Ru. For various embodiments, the plating seed layer may be deposited using a chemical vapor deposition process. In some embodiments, other suitable deposition techniques, such as atomic layer deposition (ALD), can be used to form the plating seed layer.

At step 212, a magnetic material layer is formed, possibly over the plating seed layer at step 210. In several embodiments, the magnetic material may comprise a high moment magnetic material, and may include such materials as NiFe, CoNiFe, or CoFe.

In various embodiments, the process can perform the sequence of actions in a different order, can skip one or more of the actions, or can perform additional actions. Additionally, in some embodiments, one or more of the actions may be performed simultaneously.

FIG. 3 is a transmission electron microscope (TEM) image of a an exemplary substrate structure in accordance with some embodiments. The TEM image depicts a film stack 300, comprising a CoFe layer 302, a chemical vapor deposition (CVD) Ru layer 304, a physical vapor deposited (PVD) Ru adhesion layer 306, and an amorphous seed layer 308. The film stack further comprises a mask layer 310, an insulator substrate 312, and a lower substrate or base layer 314. As depicted, the chemical vapor deposition (CVD) Ru layer 304 has smooth surface and uniform thickness at all locations and is free of delamination. Additionally, there is no presence of delamination between the CVD Ru layer 304, the PVD Ru adhesion layer 306, and the amorphous seed layer 308.

FIG. 4 is a diagram illustrating an exemplary disk drive 400 including a read-write the head 404 that can be created in accordance with some embodiments. Disk drive 400 may include one or more disks to store data. The disks 410 reside on a spindle assembly 408 that is mounted to drive housing 412. Data may be stored along tracks in the magnetic recording layer of one of the disks 410. The reading and writing of data is accomplished with the head 404 that has both read and write elements. The write element is used to alter the properties of the perpendicular magnetic recording layer of disk 410. In some embodiments, the head 404 may have one of the structures depicted in FIG. 1G. Additionally, for some embodiments, the head 404 may have magneto-resistive (MR) or giant magneto-resistive (GMR) elements. In further embodiments, the head 404 may be another type of head, for example, an inductive read/write head or a Hall effect head. In various embodiments, the disk drive 400 may a perpendicular magnetic recording (PMR) drive, and the head 404 may be suitable for perpendicular magnetic recording (PMR). A spindle motor (not shown) rotates the spindle assembly 408 and, thereby, disks 410 to position the head 404 at a particular location along a desired disk track. The position of the head 404 relative to the disks 410 may be controlled by position control circuitry 406.

In the foregoing specification, embodiments of the invention have been described with reference to specific exemplary features thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and figures are, accordingly, to be regarded in an illustrative rather than a restrictive sense. 

What is claimed is:
 1. A method for forming magnetic recording pole, comprising: forming an insulator layer; forming a trench in the insulator layer; forming an amorphous seed layer over the insulator layer; forming an adhesion layer over the amorphous seed layer, the adhesion layer comprising a physical vapor deposited (PVD) noble metal; forming a plating seed layer over the adhesion layer, the plating seed layer comprising chemical vapor deposited (CVD) Ru; and forming a magnetic material layer over and in contact with the plating seed layer.
 2. The method of claim 1, wherein forming the magnetic material layer involves a plating process.
 3. The method of claim 1, wherein forming the trench in the insulator layer comprises removing a portion of the insulator.
 4. The method of claim 3, wherein forming the trench in the insulator layer further comprises depositing a surface treatment material on the insulator layer.
 5. The method of claim 1, wherein forming the amorphous seed layer over the insulator layer comprises depositing the amorphous seed layer over the trench and over areas of the insulator layer extending beyond the trench.
 6. The method of claim 1, wherein forming the amorphous seed layer over the insulator layer comprises depositing a metal film over the insulator layer and oxidizing the metal film.
 7. The method of claim 1, wherein the PVD noble metal comprises Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au.
 8. The method of claim 1, wherein the amorphous seed layer comprises a metal oxide, a metal nitride, or metal alloy.
 9. The method of claim 1, wherein the amorphous seed layer comprises TaO_(x), TiO_(x), AlO_(x), SiO_(x), WO_(x), HfO_(x), NbO_(x), or ZrO_(x).
 10. The method of claim 1, wherein the chemical vapor deposited (CVD) Ru comprises RuO₄.
 11. The method of claim 1, wherein the insulator layer comprises alumina.
 12. The method of claim 1, wherein the magnetic material layer comprises NiFe or CoFe. 